Arc discharge lamps are being developed and evaluated for use in vehicles. Arc discharge lamps may last the life of a vehicle, while being more efficient than a filamented lamp. A major problem with arc discharge vehicle lamps vehicles is the needed to start the lamp quickly. After being switched off, and while still hot, the lamp must still be capable of being turned back on quickly. The residual hot gases in the lamp inhibit a restart arc, so restarting a hot lamp, generally requires a high voltage to jump the arc across the electrode gap. Restart voltages therefore may be 20,000 volts or more. Unfortunately, the high voltage intended to induce an arc inside the capsule, may improperly induce an arc between the leads outside the lamp capsule. The high starting voltages therefore make lead separation or lead insulation highly desirable. Overall capsule designs may help control the high voltages, such as double ended configurations and wide press single ended tubes where the lamp lead separations may be 2 or 3 centimeters. Double ended and wide seal lamps are inconvenient to integrate into a whole lamp design. On the other hand, single ended lamps are easier to mount in an optical design, safer, in that less wiring is used, easier to manufacture, and have a lower material cost; they are inherently harder to insulate with regard to interlead arc over. The side by side leads in a single ended lamp are a problem to insulate. There is then a need for a well insulated, single ended arc discharge lamp.
U.S. Pat. No. 4,734,612 issued to Hiroki Sasaki et al for High Pressure Metal Vapor Discharge Lamp on Mar. 29, 1988 shows as press sealed arc discharge lamp. One of the electrode leads is enclosed in glass and partially captured in the press seal